Fuel tank vent and pressurisation
 

Mr Vortex
Finally as promised, here is a schematic of the AFT part of the fuel vent system. As you can tsee the fin intake pressurises the air space above tank 11, and hence, via the Scavenge Tank air-space, the remaining tanks. (Also you can see the Trim Pipe Drain Vaves you were asking about.



Regards Dude :Ohttp://i1237.photobucket.com/albums/...onc11/Vent.jpg

Well I have to say this is a brilliant thread. :ok:

I stumbled upon it by accident and been catching up on it when I had a spare moment and have found it completely riveting and it has whiled away many hours over the past month.

I’m ex-RAF and spent the last ten years working as an engine bloke on the T aeroplane & RB199. We were always told there were many parallels with Concorde & the Olympus 593 – TBT/T7 Gauges, Optical Pyrometers, EPC Coils on-engine FCU’s, Vapour Core Pump for reheat fuel as well and the like. I attended the RR Manufactures course for two weeks at the Patchway Works and spent a day at the Concorde Museum seeing the similarities with the Electronic Control Units too though Lucas Aerospace made the MECU’s or GR1/4 (& DECU’s on the F3’s).

Also while on the course the distinguished RR Instructor Gent filled up in with various snippets of Engine History too such as the Vaporisers which were fitted to RB199 & the later models of Olympus 593 were originally Armstrong Sidderly designed for the Sapphire, also I learned the whole 15 Stage Sapphire Compressor was lifted completely and fitted to later Avon’s as it worked better.

I was at Leuchars in the early 80’s and the Open Golf peeps all arrived in one of these magnificent lady’s – the visit was notable for several things; someone fired off an escape chute!!! – What does this little handle do on the Main Oleo ??? whoosh ! and after the dusk take off the pilot beat the place up several times in full reheat !!!!

My last place of work before I was de-mobbed was at the RAF Marham Engine bay and I had the good fortune to meet an RR Technician called Phil (second name escapes me) but he was part of the team of RR Controls Engineers during the Hot & High Trials. He said they used to modify the three “Amps” for each Engine control – Lane1, Lane 2 & Reheat on the fly and the aircraft often flew with different schedules installed on all four engines – I think the aircraft at Duxford has these still fitted in the racks (??M2Dude??) but that’s another Tonka thing too; three control lanes. Were all these Amps combined into one black box??

They are always Amps in RR Speak?? The Spey 202 had “Amps” in its reheat system too.

I was lucky to find a job with the TVOC in 2001 until they ran out of money (as they do) and worked to have their flight worthy Olympus 20202’s tested at RR Ansty but left before that happened. In fact I don’t know if it did happen though it was a CAA requirement. While I was there we were working with Alan Rolfe & Mike Batchelor of the RR Historic Engine Department were offering support too. (593’s were their responsibility also !!! Historic !!!) but I think that was unofficial until there was an agreement about the costs.

After that I worked in industrial applications of Olympus (and Avon) and worked on many installed Olympus in power generation but based on the 200 Series – I think the 300 was thought to be too fragile. But I did have a good look at Olympus 2008/003 Still in good working order in Jersey on the Channel Islands with it’s Bristol Sidderly Name plate on it. They didn't have Inlet Guide Vanes as the 300's had but just 6 Forward Bearing Supports, hollow with anti -Icing air blown though, controlled by a Garret Air Valve.

I never saw a DEBOW sort of function on the Industrials but there is a critical N1 speed which has to be avoided because the LP Turbine Disc can fail. The Trouble with that speed range is that it is right where the usefull power is produced!!! Was there any Normal Operating Range RPM's which had to be avoided on the 593 ?

Again thanks very much for all the fascinating information here’s to another 42 pages!!:D Sorry to have rambled on so much :uhoh:

Howie

howiehowie93
Welcome aboard and thank you for your kind words; I am so glad you enjoy our thread. You are in good company here also, many of the 'more mature' vintage Concorde people :}(like me) are ex-RAF. (And some of the pilots were ex-RN also, but no one is perfect:D... only joking guys).
It is a matter of pride/embarrassment for me that up to the end of 2003, I'd only ever really 'known' two aircraft; the C-130 and Concorde:).
I was really interested in some of the RB199/Olympus similarities; TBP was tried on the development aircraft for engine control TET calculation, but Rolls-Royce were unhappy with the performance and abandoned TBP in favour of indirectly computing TET as a function of T1 (intake TAT) and EGT (T7). (And this meant the removal of the four TBP amplifiers too... we had even more black boxes then.
As for the three 'control amps' you were speaking of, I'm 99% sure that A/C 101, G-AXDN still does have the units you described fitted. The ECUs (or ECAs as they were sometimes called) were a highly complex analog control unit built by Ultra Electronics. They could be quite a headache sometimes in terms of reliability, but would generally perform flawlessly in terms of engine control. As with any analog box, control law changes in the field were not too straightforward and a soldering iron was the flight test engineers best friend here. The Reheat Amp was built by ELECMA (the electronics arm of SNECMA) and unlike some of the other components in the reheat system, was a beautifully designed and constructed unit. Very few reheat failures (and there were many) were attributed to the 'box' itself. The main fragility with the reheat system was the ignition system used (a 20 KV swirl ignitor, which you will see is covered previously in the thread). We (BA/RR) were seriously looking at one point of investigatng the use of 'hot streak' injection as a backup ignition source, which I believe was used in the 199 (?), but it unfortunately never happened. The Plessey DECU that was tried on A/C 202 (G-BBDG) DID combine main engine control and reheat, but unfortunately was never taken up for the production A/C, and so we were left withe the '3 AMPS' as you so eloquently describe. We had a total of THIRTY ONE control units associated with powerplant control on Concorde; might be a little different now methinks :ok:]
Thanks for some of the fascinating engine history snippets you shared with us, although purists might regard it as being 'off topic' I personally think this rather unique thread is all the better for your contribution here,
I think it is great that you are working with industrial Olympuses, all part of the family tree. I will dig out the verboten sustained N1 speed band for the 593, it certainly WAS a fact though.
Thanks from all of us for your contribution here Howie, keep on posting.

Regards
Dude :O

Respectfully, can I also add my thanks to the knowledgeable contributions to this thread - to hear from the folks at the sharp-end of this magnificent aircraft, the deep insight and great affection for this amazing aircraft is truly a rare honor in this day and age. Thank you one and all. So far I have read this entire thread and look forward each and every day to what might get added.

While I'm here, can anyone direct me to a good place to read up on the TSR2?

Thanks, GY

Thanks M2Dude.

Yes Hot Streak Reheat Ignition on the RB199. Only problem was the Injector was right underneath (or perhaps on top is more accurate! :ugh:) of the Reheat FCU and as it jutted out into the Combustor it was often blocking with carbon :{. so either - off with the RHFCU or disconnet the pipe and try the OM15/Landrover Speedo cable cleaning out trick. There was eventually a test set to tell you if it was still blocked (helpfull - NOT).

I'd left by this time but I was told RR came up with a way of back flushing combustor Pressure to clear it out with some success.

regards
HH93

tsr2
 

Hi GY
try this link
http://www.rafmuseum.org.uk/research/documents/Journal%2017B%20-%20TSR2%20with%20Hindsight.pdf…
rod

Here is the page with all the journals just in case the above does not work (did not work for me). Fascinating Reading.

howiehowie93
The whole idea of adapting hotstreak injection came from our Rolls-Royce rep', who spent many years on RB199 development. We'd even identified the position on the Olympus 593 for the injector itself; un unused start atomiser port, but as I reluctantly said before, it was not to be.
Apart from ignition issues the other main problems were reheat instability and reheat 'coming in with a thump', this particular malady being generally confined to transonic acceleration and not take-off.
The instability issue was caused by either an open circuit/high resistance fuel metering valve tacho (only rate feedback was used here) or more commonly contamination of the RFCU umbilical electrical connector. The connector itself was originally located high up the side of the engine, close to the combustion area, was barely accessable and was a total nightmare in terms of reliability. After a great deal of pressure from us (BA) SNECMA agreed to effectively relocate the connector at the bottom of the engine and the majority of our stability problems almost disapperared overnight.
The 'reheat in with a thump issue was a real beaut'. For transonic acceleration a much lower ratio of Fr/Fe (reheat fuel flow/engine fuel flow) was used than for take-off. (0.45 as opposed to 0.78) and therefore the opening rate of the fuel metering valve required damping, this being achieved by using a metered orifice inside the RFCU that applied a small amount of servo fuel pressure to one side of the valve to achieve the damping. Trouble was, any contaminants in the reheat fuel system would progressively clog up the orifice and kill our daming stone dead; the end result being the FMV banging wide open and hence the 'thump'. The only remedy for this problem was to replace the RFCU. SNECMA, in a truly classic feat of engineering produced a filter across this orifice, in order to prevent it getting clogged. Anyone see a problem with this? Yep, the filter itself would clog up and we got our beloved thump back. :EThe only remedy for this problem was again to replace the :mad: RFCU. The contaminants were often as a result of RFCU build issues; this issue was never truly resolved.
I checked and found the dodgy sustained N1 band for the Olympus 593, this was 88-91% N1. This figure was never an issue in service as at cruise ISA -7 and above conditions the N1 was always run at the flat rate limit of 101.5%. Below ISA -7 the intake system would progressively reduce N1 as a function of intake local Mach Number, falling to 97.4% at ISA -24. (The coldest cruise conditions I personally ever saw was ISA - 25 (that's -81.5 degrees C folks) between BAH and BKK.
The controlled N1 at all other 'non cruise' phases was always in the upper 90's, well away from our blade resonance area.

jodeliste and Alpine Flyer
Thank you both for the TSR-2 information, it makes amazing reading (what a truly magnificent aircraft) , and as Concorde's military cousin, discussion here is in my opinion most waranted.

Regards
Dude :O

M2Dude

There was an unconfirmed report - so no doubt completely baseless - that ...er...another operator... noticed a rather unusual but highly favourable wind component on a JFK...er...Easterly... crossing, as they passed through FL520 or so, giving them a magnificent groundspeed.

Deciding that they would like to maintain this groundspeed, they went ALT HOLD and MACH HOLD at around FL530. They maintained their groundspeed, so the story goes, but the autothrottle then progressively reduced the N1, as the aircraft weight reduced, over the next couple of hours, into the prohibited range!

Did you ever hear of any such event?

Best Regards

Bellerophon

M2 Dude
I think TSR2 is probably my favorite ever, I once got a job interview at Cranfield not long after it was cancelled just so that I could go and look at it in their museum. :O I remember being amazed at how large it was
cheers
rod

Can somebody explain to a "Volts and Amps and Ohms ancient" what "hotstreak injection" is/was (without getting scabrous)?

Many thanks for that story, M2dude, and no problem understanding it that one.

Same here.
Purists be damned.
Concorde wasn't created 'ab nihilo', in a vacuum, as it were.
So, placing her squarely in the aviation world of the time should be part of the thread and the story.

In my own field (avionics) both TSR-2 and Concorde are almost "snapshots" of technology at a given time, a technology which was changing very rapidly.

I may go and rabbit on about that some more, one of these days, but describing what happened in the avioncs/electronics field is always more difficult than the purely mechanical, engine and structure progress.

CJ

PS A few years ago I had a chance to have a close look at some of the TSR-2 electronics in the East Fortune (Scotland) museum.
IIRC a lot of it was Ferranti.
It was an eye-opener as to how much technology had already changed from TSR-2 to Concorde.

Bellerophon
Ahhh this 'other operator' (I'd quite forgotten our code for *** ******). And as for this obviously baseless story ;).... er yes it did happen. I should really have qualified my post and said 'The controlled N1 as long as the aeroplane was operated CORRECTLY was always at least in the upper 90's, well away from our blade resonance area'. I don't quite recall after the engines were removed post-flight (At Rolls-Royce's insistance) whether the entire LP compressor sections or just the first few stages had to be replaced at the engine overhaul base. In either case it was a rather expensive piece of experimentation.

ChristiaanJ
Certainly my friend (but hey, remember that I'm an old Volts and Amps and Ohms ancient at heart too :p).
The lighting of a reheat flame can be achieved in three ways:
1) By using an electric arc ignitor.. the least reliable system, although relatively simple in concept.
2) Catalytic ignition, where the reheat fuel is sprayed over a platinum based catalyst, spontaneously igniting. I recall that although generally reliable, eventually the catalyst compound erodes away and you are left with no ignition source.
3) Hot streak injection (or ignition). I this case a sizable jet of fuel is injected through a single injector placed the the combustion chamber of the engine, a powerful streak of flame then 'shoots out' of the turbine, and ignites the reheat fuel. Generally reliable as long as the injector itself does not carbon up (as our new friend Howiehowie93 pointed out). What amazed me with this system when we were looking at it for Concorde, was that the Olympus 593 designer I spoke to at Rolls-Royce told me that it has a negligible effect on turbine blade life, as the hottest part of the flame does not hit the blades themselves, and also of course it is a very short duration burn anyway (1 - 2 seconds).
And Christian my friend, you should indeed 'rabbit on' here about some of your observations regarding Concorde electronics technology, you have a unique insight here as (probably) the only Concorde systems designer that regularly visits 'here'. I'm sure I speak for many of us here when I say that your experiences are unique and your contributaions are always illuminating. Come on, let's have some Volts/Amps and Ohms :D

Best Regards
Dude :O

This statement has been sent to Heritage Concorde by Airbus in the UK!

It's been place on my site, but I have also placed it on here so as many as possible will get a chance to read it.

Steve



“I am sure you will receive a lot of feedback regarding the aircraft and the maintenance work that needs to be performed. In the end, however, it comes down to one key point: the owner of the aircraft, British Airways, inspected its property, and determined that while the plane was in relatively good shape, these repairs are required. As such, the maintenance and preservation work will occur. I am sure you can agree, if the maintenance and repair did not occur, the plane would only degrade further.
Reference your source’s comments below:

• Airbus at Filton, and its predecessor companies, have maintained aircraft for many years and have a highly trained and skilled workforce who understand aircraft and maintenance programs
• We have performed a visual inspection of the airframe each week since the aircraft arrived and latterly had become concerned over indications of corrosion (please do not refer to this as rust) such as blistering and cracking.
• The “holes in the fuselage” were certainly not created for TV. Our job is to maintain the aircraft, not damage it. These holes are in fact the result of corrosion in some of the lower belly panels which have been further exposed as maintenance/preparation begins. The hole in the leading edge is old damage that has been temporarily and repeatedly patched continuously over the years. We are now performing a more permanent fix.
• There are 7 windows leaking in total, including one on the flight deck which must be resealed to prevent cracking. The failure to repair leaks will present a huge risk, especially during the winter period, as window glazings can crack due to the expansion of water as it freezes, and there are very few replacements available. “

Ah, hot streak ignition, also used by P&W on the J 57 and J75 afterburners. On the wing, during a form take-off at night, one could see the brief fireball, if the burner didn't light off. A second attempt would usually work, but took a moment to "reload" the ignition source. Seemed terribly crude to me. F-100 takeoffs were fairly leisurely affairs, anyway.

The other night, crossing to England, the temps at FL 430 were very cold, on the order of ISA-12. I was thinking of this thread, wondering if those temp devs would hold into the upper levels and, if so, perfect conditions for a Concorde crossing.

GF

More Olympus stuff
 

Greetings.

Service Bulletin 0420 Industrial Olympus Gas Generator – LP Turbine Disc Cracking Safety Related Operational and inspection requirements.
to paraphrase:

Avoid steady operations in the range 5450 to 5850 RPM I believe that 100% is 8000RPM so that equates to 68 – 73%. It is ok the accelerate through that range apparently.


There seems to be a lot of history about Olympus LP Discs:
Test House 40 – I think - at RR Ansty still has the deep groves in the brickwork where an engine broke up during test.
From Wikipedia:
“XA894 flew with five Olympus engines, the standard four plus an underbelly supersonic Olympus 320 fed from a bifurcated intake starting just aft of the wing leading edge and inboard of the main intakes, in a mock-up of the BAC TSR-2 installation. This aircraft was destroyed on a fire on the ground on 3 December 1962”

I read the LP Disc did a QANTAS A380 and decided to leave the engine:
An Aviation Heritage story

So there’s nothing new in the world really :sad:

regards
HH93

This thread just gets better.
 

A couple of observations and a questionette, if I may? First, I'm feeling quite pleased with myself that I have largely understood the latest phases of discussion, re: Reheat Ignition and N1 resonance! To be fair I was a bit puzzled about 'Hot Streak' until Dude explained in a slightly different way. Then my first thought was; 'Cor crikey, isn't there enough heat on the turbine blades already?' It seems not, but it does raise the issue of TBE (TEB?) injection, a la SR71? I know the Blackbird used rather different fuel (JP8?), but is there not a similar chemical that would have done the same thing? Perhaps it was a reluctance to use 'exotic' chemicals in a civilian aeroplane?

The resonance issue is quite interesting, in that it appears to have affected all models of Olympus and was at roughly the same rpm on all. I take it that any attempt to damp specific frequency resonance would have adversely affected the performance?

Which brings me to my questionette - given that Bristol-Siddley created the original design when jet travel was still quite novel, what was it about the Olympus that made it so capable in so many guises and for so long? Not only Concorde of course, but TSR2, warships and fixed electrical generators.

Roger.

why was the Olympus so suitable
 

IMHO I'd the simplicity of the design. I have worked on many flavours of Gas Turbines since I left the RAF in 2000, GE, RR, Rustons, (EGT, RGT the same really just a name change every few years and now Siemens) oh and Solar - who I work for now - better not forget them !!

All these engines from other manufacturers have complicated systems to make them efficient:
VIGV's (Variable Inlet Guide Vanes)
VSV's (Variable Stator Vanes)
Bleed Valves
Multi Fuel Metering Valves & other valves to keep emissions under control.

The Olympus - nowt ! Two Spools and a Fuel Valve thats your lot. nothing to go wrong and being an Aeroderivative all the ancillary equipment is either bolted on underneath or away from the engine outside the enclosure. :D

The only thing I had trouble with was the burner bolts shearing off, 1/4"BSF, if never touched in a good few years !:{

Was it all still BSF on the 593? That was a Bristols thing - true RR designs are UNC (well Avons are anyway)

oh ! I forgot about the Hot Shot; when I was ground running installed RB199's there was no jump in TBT/T7, you couldn't sense it fire either, the only feel was either the Reheat lighting off with a big roar or the engine going quiet as the Nozzle opened up until the MECU noticed it hadn't lit and closed it again sharpish.

Good eh
Regards
H;)wie

Wow.....

What a thread! It has consumed many, many hours of my time, and a few groans from the missus (not that aeroplane thing again! :O ) but it has been so worth it. The level of passion, technical detail and knowledge is both breathtaking and astounding, and would make a thoroughly bloody good book IMO!

Now, from a purely hypothetical POV:

How much would it cost, do you think, that IF EADS really wanted to, using a combination of all the knowhow gained through L'Oiseau Blanc and their current lineup could they produce a 'Concorde NG'? Most importantly, would there be a market for such a beast (at the right price)?

Use something like the A321 fuselage tooling and common flightdeck as a starting point. The Pratt & Whitney PW5000 looks like it could be a mighty fine off the shelf modern Olympus 593 replacement.

There's a start, now thoughts please!! (Please don't just tell me to F**k off and stop being so stupid :ouch: )

BTW, M2Dude, ChristiaanJ, Exwok, Bellerophon, Brit 312, Landlady et al: Keep up the good work - You have restored my faith in the aviation world! Not everybody involved at the top level is an arrogant a***hole, it seems. :D Thank you sincerely.

Tom

Ok, I've got another question! I was watching "Concorde: The Comeback" on discovery turbo channel last night (just couldn't help myself!).

Really interesting stuff about how they put the kevlar into the fuel tanks etc. I don't know if anyone who posts here was in that program, but if you were - everyone was looking good!! :-) It was superb to see the genuine emotion when Concorde got her certificate back and could take to the skies once again!

Ok, so my question is - BA had to use an airframe as a test for the modifications. However, the choice of airframe seemed a strange one to me, BOAF - which I previously thought to be one of the youngest and best airframe they had (m2dude you explained that BOAF and BOAG weighed less than the previous models). So, why would BA use one of their best airframes, rather than use perhaps the most worn out of their fleet?

All in all though - great program, and lovely shots/video of the Lady, and all who cared for her, from the guys at the top running the business side to the poor guys climbing into the fuel tanks! In all honesty, I'd prefer to be doing the fuel tank side stuff myself, rather than the business side of it! Maybe the pilots had the best of all worlds! ;-)

Cheers for all the insight & information once more!

(Edit: In this program pretty much at the start, all 7 BA concordes are shown lined up in formation on the ground at (I presume) Heathrow). Just seeing them all together, all looking stunning.... breathtaking.

Wow thanks a lot M2Dude for your diagram.:ok:

I'm wonder that did Concorde has a neutal of stable stability? Did the elevon work out the same job to produce the stability like the elevator and stabilizer?

Also, I have read your post and wonder why when the temp fall below ISA-7, the AICU order the N1 to decrese?

And the final question. In the early concorde, does the pilot has ability to select the amount of afterburn thrust by rotate the area knob is that right? and why the airline remove it?

Thanks for your reply.

Best Regards